He's really good, possibly an immediate starter at ISU, but IMO he's not "KU good" in the fact that he'd probably see around 10 mins a game for them. For a JUCO, you'd have to think that he wants immediate minutes. At KU, you have to be pretty elite to get a lot of minutes, and he isn't elite.
Juiston and Lewis are both about 6'6" - 6'7", but completely different players. Juiston is "thicker", more physical, and an interior player, while Lewis is more of a 3 point shooter, slasher, quicker player. They would be very compatible together on the court, if Lewis is ready to play right away.